Flow meter indicating device

Abstract

The present invention provides a device for generating an electrical output signal representative of the flow rate through a fluid flow meter of the type having a mechanical output member movable in an amount proportional to the fluid flow rate. The device comprises the U-shaped magnet having a north and south pole and a Hall effect transducer positioned between the poles of the magnet. The transducer produces an electrical signal representative of the distance between the transducer and one of the magnetic poles. The magnet in turn is connected to the mechanical output member from the flow meter so that the magnet moves in unison with the output member from the flow meter thus varying the transducer electrical output. The output from the transducer is electrically connected to a conventional electrical indicator to produce an indication of the fluid flow rate through the flow meter.

I claim: 
     
       1. For use in conjunction with a fluid flow meter having a mechanical output member movable in an amount proportional to the fluid flow rate through the flow meter, a device for generating an electrical output representative of the flow rate through the flow meter comprising: a magnet having a north and south pole,   a transducer positioned between said poles of said magnet, said transducer producing an electrical signal representative of the distance between the transducer and one of said poles, and   means for moving said magnet to vary the distance between said one of said poles with respect to said transducer in a direction opposite to movement of the other of said poles with respect to said transducer in an amount proportional to the movement of said mechanical output member from the flow meter.   
     
     
       2. The invention as defined in claim 1 wherein said electrical signal comprises a variable voltage signal. 
     
     
       3. The invention as defined in claim 2 and comprising means for converting said voltage signal to a current proportional to said voltage. 
     
     
       4. The invention as defined in claim 1 wherein said moving means comprises means for mechanically connecting the output member to the magnet. 
     
     
       5. The invention as defined in claim 4 wherein the output member rotates an amount proportional to the flow rate and wherein said mechanical connecting means comprises a pinion secured to the output member,   a gear rack secured to the magnet, and   wherein said pinion meshed with said gear rack.